NEW YORK (AP) – Investigators are looking at a possible gas leak and pesticide canisters as they probe Thursday afternoon's explosion inside a building in New York's Chinatown that injured 12 people, 3 of them seriously.

The blast led to a fire and a partial collapse of the five-story building, which houses businesses and apartments. Four firefighters were among those with less serious injuries.

Fire officials say several so-called bug bombs were found in a first floor rear apartment and may have exploded. Still, the cause of the blaze has not been determined.

The Red Cross says it provided emergency housing for 28 adults and three children put out of their homes after a vacate order was issued for the building.